Experimental Assessment of BitTorrent Completion Time in Heterogeneous TCP/uTP Swarms

Executive Summary

BitTorrent, one of the most widespread file sharing P2P applications, recently got rid of TCP by introducing an application-level congestion control protocol named uTP. The aim of this new protocol is to efficiently use the available link capacity, while minimizing its interference with the rest of user traffic (e.g., Web, VoIP and gaming) sharing the same access bottleneck. In this paper, the authors perform an experimental study of the impact of uTP on the torrent completion time, the metric that better captures the user experience. They run BitTorrent applications in a flash crowd scenario over a dedicated cluster platform, under both homogeneous and heterogeneous swarm population.